Based on the wide range of intraclass correlation values we observed for the NeuroCom measures, clinicians and researchers alike should establish the reliability of LOS testing for their own clinics and laboratories. The low to moderate reliability outcomes observed for the Biodex measures were not of sufficient magnitude for us to recommend using the LOS measures from this system as the gold standard. The moderate Pearson interclass correlations we observed suggest that the Biodex and NeuroCom postural stability systems provided unique information. In this study of healthy participants, the concurrent and construct validity of the Biodex and NeuroCom LOS tests were not definitively established. We recommend that this study be repeated with a clinical population to further explore the matter.

Currently used measures of knee stability and function for ACL reconstructed knees have not gained universal acceptance. Clinical test results often are given more value than the patient's subjective evaluation of the surgical outcome. This study was designed to identify specific knee stability and function variables that were most predictive of the patient's rating of knee function following one of two types of combined (intraarticular and extraarticular) ACL reconstruction procedures. Individual measures of knee stability and function were also evaluated for differences between contralateral operated and nonoperated limbs. Postoperative and healthy contralateral knees of 51 male and female patients aged 18 to 49 years (mean, 23.7 years) were evaluated on a battery of tests at an average of 48.0 months after surgery (range, 24 to 101 months). All subjects possessed a normal contralateral knee for comparative purposes. The results of this retrospective study indicated that the variables selected were not highly correlated with, nor could they effectively predict, the patients' perceptions of postoperative knee status as measured by the Knee Function Rating Form (KFR). Statistically significant differences (P less than 0.001) between operated and nonoperated knees were found for 9 of 11 variables analyzed. The data suggest that patients' perceptions of postoperative knee status were independent of the results of static and dynamic clinical tests commonly used to assess knee stability and function. Postoperative deficits of up to 30% between the surgically reconstructed and normal contralateral knees on specific measures of knee stability and function did not greatly influence the patients' perceptions of knee function. Development of new, more specific dynamic tests may be necessary before stronger relationships between clinical test results and patients' perceptions of knee status in the ACL reconstructed knee can be realized.

This study compared the relative accuracy, similarity, and average error of 7 prediction equations (Brzycki) for estimating 1-repetition maximum (1-RM) performance of older sedentary adults using Hammer Strength Iso-Lateral resistance exercise machines. Data were collected from 49 apparently healthy volunteers (26 males, 23 females) aged 53.55 ± 3.34 (mean ± SD) years. 1-RM scores were obtained for biceps curl, chest press, high latissimus dorsi (lat) pull, incline chest press, leg curl, leg extension, low lat pull, leg press, shoulder press, and triceps extension. Repetitions to fatigue (RTF) for each exercise were determined by assigning each subject a percentage of his or her 1-RM ranging from 50% to 90%. Subjects performed as many repetitions as possible with the predetermined resistance. Predicted 1-RM (1-RMP) was evaluated by relative accuracy (correlation between 1-RM and 1-RMP), similarity (paired t-test between 1-RM and 1-RMP), and average error (sqrt[Σ(1RMP -1RM) 2 /(n -1)]). Relative accuracy, similarity, and average error improved significantly and gender differences were minimal when RTF ≤ 10. Accuracy of prediction equations varied over different resistance exercises. The Mayhew, Ball, Arnold et al. (1992), Epley (1985, and Wathen (1994) formulas evidenced the lowest average error (AE) and highest relative accuracy over the resistance exercises examined; however, both absolute AE and AE expressed as a percent of mean 1-RM were quite high for all formulas over all exercises.

The observed correlations did not support our hypothesis that the relationships between sex hormone levels and reflex activity or between sex hormone levels and ATD would be different for women compared with men. If sex hormone concentrations significantly contribute to anterior cruciate ligament ruptures because of changes in laxity or in motoneuron excitability, their mechanism of action is likely multifactorial and complex.

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